Winter Birds

The Glade Trust has been doing a Winter survey of resident and winter migrants in conjunction with the British Trust of Ornithology ( BTO) for the past 4 years. It's official name is Winter CES, or constant effort site.

Basically mist nets are erected in the same place each year, and when weather permits at similar times and days for eight sessions over a 16 week period, Nov to Feb. Birds, mainly passerine, are caught , extracted by trained permit holding bird ringers; who weigh, measure, age and sex the birds then the birds are released asap to continue their foraging/ feeding.

The information gathered is inputted onto the national database were studies are conducted, and statistics can be analysed.

What does the data gathered show us? The information tells us how are birds are doing from the previous season breeding, to longevity of species to the various peaks and troughs of mortality due to habitat loss, disease, and unpredictable weather. Eg. Blue Tits, gather moth caterpillars to feed the nestlings, however, if there is a crash in caterpillars then brood success is low. Nestlings can starve, nest abandoned or fledglings are low in number plus adult mortality is also greater.

I will add the data when inputting is complete and the picture is clearer. At the moment certain birds like Blue and Great Tit numbers are down, with Goldfinch and Siskin being up.